Some precautions:
=> Experiments involving poisonous gases like Nitrogen DIOXIDE, Ammonia and Bromine -> Carry out the exp. in Fume Cupboard or in a well Ventilated Room.
=> Experiments involving heat -> Use a polystyrene cup for insulation to prevent heat loss! + Always take the same initial readings for better accuracy;
=> Experiments involving Acids, Liquids or Solids -> Always use the same concentration; Same Volumes; Same Surface Area or Same Masses exceptions are some variables!
=> Experiment involving Crystallisation -> Allow to cool SLOWLY and Use more water and more salt for better results!
SOME COMMON and USEFUL precautions for all experiments (use these when your mind is BLANK)
=> Repetition of the exp.
=>Taking Average > Put your tie in shorts
=> Use Goggles
=> Taking measurements carefully and multiple measurements , to achieve accuracy ( by finding the average )
=> When drawing the best fit line in a graph , do not include points that seem to be out of the curve ,use a sharp and make the curve as smooth as possible , and remember to plot the independent Variable ( Temprature in a Time-of-reaction ( Y ) / Temprature ( X ) graph ) and NEVER forget to write the labels.

Tests
1.For Water:
> By adding anhydrous Copper(II) Sulphate , which will turn from white to blue.
> By adding anhydrous Cobalt(II) chloride , which will turn from blue to pink.

3.For purity of substance
Solids => Test for melting point , if it is the correct value ( like the data says ) it is pure , if not, it is impure. e.g. Ice at 0 C°
Liquids => Test for boiling point , if it is the correct value ( like the data says ) it is pure , if not, it is impure. e.g. Water at 100 C°

COLLECTION TECHNIQUES:
=> upward delivery is for -> gases less dense than air (Hydrogen and Ammonia)
=> Downward delivery is for -> gases more dense than air (Carbon Dioxide
=> Displacement of water method -> insoluble gases ( Methane )

Fermentation:
=> Glucose and Yeast are used! (just rememeber that Yeat contains enzymes -> Biological Catalysts)
=> Suitable Temperature 37 degrees (Optimum for Enzyme)
=> Bung is used -> To Let Carbon Dioxide out, and prevent the entry of Oxygen.
=> Why is Oxygen's entry prevented (-> because it'l oxidize the alcohol to Carboxylic Acid and also it'l affect the anaerobic respiration)
=> Why does the reaction stop? -> Due to an excess in the conc. of alcohol, Yeast dies. Or Glucose finishes up!

Chromatography:
=> Draw a baseline with a pencil (pencil being insoluble) about 1-2 cm above the end of the chromatogram
=> Use a pipette to put a concentrated spot of dye on the paper
=> Dip it in a solvent (Water, if it's soluble in it otherwise an organic solvent e.g Ethanol)
=> the solvent level MUST be below the baseline
=> The solvent would start to rise up the paper producing a no. of spots (depending on the no. of dyes present in the substance)
=> Spray a locating agent for colourless dyes like amino acids or simple sugars
=> Or identify with RF value (formula = (distance moved by the dye)/(distance moved by the solvent)

Hey guys, Assalam-o-Alaikum
These are some of the tips for Chemistry ATP (both O-level and IGCSE)

Some precautions:
=> Experiments involving poisonous gases like Nitrogen, Ammonia and Bromine -> Carry out the exp. in Fume Cupboard or in a well Ventilated Room.
=> Experiments involving heat -> Use a polystyrene cup for insulation to prevent heat loss! + Always take the same initial readings for better accuracy;
=> Experiments involving Acids, Liquids or Solids -> Always use the same concentration; Same Volumes; Same Surface Area or Same Masses exceptions are some variables!
=> Experiment involving Crystallisation -> Allow to cool SLOWLY and Use more water and more salt for better results!
SOME COMMON and USEFUL precautions for all experiments (use these when your mind is BLANK)
=> Repetition of the exp.
=>Taking Average > Put your tie in shorts
=> Use Goggles
=> Taking measurements carefully and multiple measurements , to achieve accuracy ( by finding the average )
=> When drawing the best fit line in a graph , do not include points that seem to be out of the curve ,use a sharp and make the curve as smooth as possible , and remember to plot the independent Variable ( Temprature in a Time-of-reaction ( Y ) / Temprature ( X ) graph ) and NEVER forget to write the labels.

Tests
1.For Water:
> By adding anhydrous Copper(II) Sulphate , which will turn from white to blue.
> By adding anhydrous Cobalt(II) chloride , which will turn from blue to pink.

3.For purity of substance
Solids => Test for melting point , if it is the correct value ( like the data says ) it is pure , if not, it is impure. e.g. Ice at 0 C°
Liquids => Test for boiling point , if it is the correct value ( like the data says ) it is pure , if not, it is impure. e.g. Water at 100 C°

COLLECTION TECHNIQUES:
=> upward delivery is for -> gases less dense than air (Hydrogen and Ammonia)
=> Downward delivery is for -> gases more dense than air (Carbon Dioxide
=> Displacement of water method -> insoluble gases ( Methane )

Fermentation:
=> Glucose and Yeast are used! (just rememeber that Yeat contains enzymes -> Biological Catalysts)
=> Suitable Temperature 37 degrees (Optimum for Enzyme)
=> Bung is used -> To Let Carbon Dioxide out, and prevent the entry of Oxygen.
=> Why is Oxygen's entry prevented (-> because it'l oxidize the alcohol to Carboxylic Acid and also it'l affect the anaerobic respiration)
=> Why does the reaction stop? -> Due to an excess in the conc. of alcohol, Yeast dies. Or Glucose finishes up!

Chromatography:
=> Draw a baseline with a pencil (pencil being insoluble) about 1-2 cm above the end of the chromatogram
=> Use a pipette to put a concentrated spot of dye on the paper
=> Dip it in a solvent (Water, if it's soluble in it otherwise an organic solvent e.g Ethanol)
=> the solvent level MUST be below the baseline
=> The solvent would start to rise up the paper producing a no. of spots (depending on the no. of dyes present in the substance)
=> Spray a locating agent for colourless dyes like amino acids or simple sugars
=> Or identify with RF value (formula = (distance moved by the dye)/(distance moved by the solvent)

=> All metals are reducing agents! (Mention the Group I metals)
=> Dehydrating Agents : Sulfuring Acid
=> Drying agent : Calcium Oxide
I had to write this all TWICE ( because of this net) <= Always copy your post (once) before posting! (My advice)
Correct me where I'm wrong and also post your own tips here!
Topic is 'sticky' for a day.
Just pray for me!
And Best of Luck

Click to expand...

For precautions .. Tie your hair at the back .. Wear gloves .. Lab suit ! Correction was required as for all fellow XPF people !

Hey guys, Assalam-o-Alaikum
These are some of the tips for Chemistry ATP (both O-level and IGCSE)

Some precautions:
=> Experiments involving poisonous gases like Nitrogen, Ammonia and Bromine -> Carry out the exp. in Fume Cupboard or in a well Ventilated Room.
=> Experiments involving heat -> Use a polystyrene cup for insulation to prevent heat loss! + Always take the same initial readings for better accuracy;
=> Experiments involving Acids, Liquids or Solids -> Always use the same concentration; Same Volumes; Same Surface Area or Same Masses exceptions are some variables!
=> Experiment involving Crystallisation -> Allow to cool SLOWLY and Use more water and more salt for better results!
SOME COMMON and USEFUL precautions for all experiments (use these when your mind is BLANK)
=> Repetition of the exp.
=>Taking Average > Put your tie in shorts
=> Use Goggles
=> Taking measurements carefully and multiple measurements , to achieve accuracy ( by finding the average )
=> When drawing the best fit line in a graph , do not include points that seem to be out of the curve ,use a sharp and make the curve as smooth as possible , and remember to plot the independent Variable ( Temprature in a Time-of-reaction ( Y ) / Temprature ( X ) graph ) and NEVER forget to write the labels.

Tests
1.For Water:
> By adding anhydrous Copper(II) Sulphate , which will turn from white to blue.
> By adding anhydrous Cobalt(II) chloride , which will turn from blue to pink.

3.For purity of substance
Solids => Test for melting point , if it is the correct value ( like the data says ) it is pure , if not, it is impure. e.g. Ice at 0 C°
Liquids => Test for boiling point , if it is the correct value ( like the data says ) it is pure , if not, it is impure. e.g. Water at 100 C°

COLLECTION TECHNIQUES:
=> upward delivery is for -> gases less dense than air (Hydrogen and Ammonia)
=> Downward delivery is for -> gases more dense than air (Carbon Dioxide
=> Displacement of water method -> insoluble gases ( Methane )

Fermentation:
=> Glucose and Yeast are used! (just rememeber that Yeat contains enzymes -> Biological Catalysts)
=> Suitable Temperature 37 degrees (Optimum for Enzyme)
=> Bung is used -> To Let Carbon Dioxide out, and prevent the entry of Oxygen.
=> Why is Oxygen's entry prevented (-> because it'l oxidize the alcohol to Carboxylic Acid and also it'l affect the anaerobic respiration)
=> Why does the reaction stop? -> Due to an excess in the conc. of alcohol, Yeast dies. Or Glucose finishes up!

Chromatography:
=> Draw a baseline with a pencil (pencil being insoluble) about 1-2 cm above the end of the chromatogram
=> Use a pipette to put a concentrated spot of dye on the paper
=> Dip it in a solvent (Water, if it's soluble in it otherwise an organic solvent e.g Ethanol)
=> the solvent level MUST be below the baseline
=> The solvent would start to rise up the paper producing a no. of spots (depending on the no. of dyes present in the substance)
=> Spray a locating agent for colourless dyes like amino acids or simple sugars
=> Or identify with RF value (formula = (distance moved by the dye)/(distance moved by the solvent)

=> All metals are reducing agents! (Mention the Group I metals)
=> Dehydrating Agents : Sulfuring Acid
=> Drying agent : Calcium Oxide
I had to write this all TWICE ( because of this net) <= Always copy your post (once) before posting! (My advice)
Correct me where I'm wrong and also post your own tips here!
Topic is 'sticky' for a day.
Just pray for me!
And Best of Luck